Here are a couple of links that can at least give you some clue. (That's one reason it can be nice to have a seasoned agent: they usually have a better idea than you do what your market value might be.)

The last one loads strangely on my PC; be sure to scroll down because it's very helpful.

These only discuss advances. There are lots of other things to worry about in a book deal. I recommend extensive Internet searches combined with several of the excellent books on how to read a book contract before you sign anything.

I think I just wrote about this somewhere ... oh yeah, in my blog where I can insult people on my own nickel. Anyway, the post refers to Writer's Digest's great article "What's the Deal?" in the January issue. In it Tom Connor says, " In most cases, for first books, publishers pay anywhere from a $2,500 to a $15,000 advance for fiction, slightly more for nonfiction" and a lot of other useful remarks.

It's very difficult to say what an average novel advance is. Most who try to give such figures lump all publishers into one group, and doing so tells you nothing. A tiny publisher may offer no advance at all, or one that if only a few hundred dollars. Mainstream commercial publishers typically offer advances of at least $7,500, and often higher.

One of those links above states that some writers defer advances, prefering to wait for royalties. Yeah, right. Such a writer is either already selling bazillions of books, or doesn't want to sell any books, ever. The only writer I know of who no longer takes advances is Stephen King, and this is only because he takes a percentage of the profits. This will not work for anyone who isn't routinely on the bestseller lists, and wouldn't work for many who are.

Averages are also skewed by the fact that a tiny few first time novelists receive six or seven figure advances. Don't count on it.

The median does mean much more than average, but even here it doesn't tell you much because exceptions are the rule.

In all honesty, a good deal is when a publisher offers you as much or more than they offer other first time novelists, and a contract that doesn't rip you off. Any decent agent will see to this.

New riters think a little too much about the advance they'll receive. What matters is how well the novel sells. How ell a book sells is pretty much the sole determiner is whether or not you can earn a living from writing, and more important, the determiner in whether or not you can stay published.

Selling a first novel is tough, but getting published often isn't as tough as staying published. If your books do not make a profit for the publisher, or even if they make a small proit that puts you in the midlist, sooner or later you'll be dropper. Finding another publisher after this happens is much tougher than finding a publisher in the first place.

Three out of four first novels do not earn back their advance, whatever the size of the advance, and publishers do not give a writer as many chances to write their way out of a hole as they once did.

My advice for new writers is to not worry too much about the size of the advance. Worry more about the quality of the publisher, and about trying to write a second book that's better than the first.

I'd add that too many publishers with poor reputations offer little to no advance. I'd think long and hard before I signed such a contract. If you're getting no advance, that may be an indication that the publisher expects the book not to earn very much. If they normally give no advance, that may indicate that they expect all of their books not to earn very much. That may mean they're earning their living off the few copies that you and yor friends will buy. That's a nice way to have a book to share with family and friends, but it's an unbelievably painful way to launch a bestselling career.

It's worth saying again that in normal book deals with reputable publishers, the author pays nothing: no editing fees, etc. Also, in normal book deals with reputable publishers, the author expects that the publisher will do all the marketing. So the author should have to worry about no marketing expenses, either.

James is absolutely right that quality of publishing house is key. Do an advanced search in Amazon.com on your publisher and this year or last year. Then check to see what sorts of formal reviews they've gotten and where those books are in the sales rank. Your publisher may hold up one or two bestsellers to you, but if all the rest of their current books are in the millions, I'd say that's a bad sign. And if there are no reviews (and by reviews, I mean from the review journals, not from readers), that's a disastrous sign. I have a friend whose first book sold 20,000 copies. That's very respectable! But her next manuscript had a different feel and was tougher to love. When she rejected her old house's offer on it, hoping to do better, she found nothing but shut doors. So she went with a university press, and that press didn't even have a policy of sending the book out for reviews. That's how libraries and booksellers get to know about a book. Her career is now dead in the water, and she got so discouraged that she hasn't written another manuscript.

If you're with a reputable publisher of any magnitude at all, an advance of several thousand dollars is reasonable. It's true that the publisher will not think as kindly of you if this advance doesn't get earned out. But it's also true that other publishers won't think much of you if your books get awful reviews and sell only a few hundred copies, anyway, regardless of whether or not you earned out a practically nonexistent advance. My agent had to show my new publishing house sales numbers on my published books. She didn't have to disclose the size of my old advances. My new house doesn't even know if I've earned out or not. They just care how the books are doing.

Don't be afraid of a decent advance. Either you'll make it in this business or not, and only your next manuscript will determine whether you'll be published again. On the other hand, if there's no advance (or a token advance), ask yourself WHY. And don't sign until you get a VERY good answer.